Pierrette and Alexa Days are twins, daughters of Mr Days and Mrs Days. They have a brother, Orion Days. During the First Wizarding War, they were part of the Abscondita, a group for protection and saftey, along with their brother, his wife and their child. Pierrette and Alex were murdered by Alsius Selwyn at the Battle of Hogwarts in revenge for Orion having a child with his sister, Calesca. Marvell, their nephew, was close enough to them to kill Selwyn in revenge, and for him to name his two daughters after them, Kasia Alexa Days and Anelia Pierrette Days.